1. Field
The present disclosure relates to single focal length lens systems, interchangeable lens apparatuses, and camera systems.
2. Description of the Related Art
In recent years, interchangeable-lens type digital camera systems (also referred to simply as “camera systems”, hereinafter) have been spreading rapidly. Such a camera system includes: a camera body having an image sensor such as a CCD (Charge Coupled Device), a CMOS (Complementary Metal-Oxide Semiconductor) or the like; and an interchangeable lens apparatus including an imaging lens system for forming an optical image on a light acceptance surface of the image sensor.
The camera system uses an image sensor larger than an image sensor mounted in a compact digital camera, and therefore, can take high-sensitive and high-quality images. Further, the camera system realizes high-speed focusing and high-speed image processing after image taking, and easy replacement of an interchangeable lens apparatus in accordance with a desired scene.
An interchangeable lens apparatus including a single focal length lens system is popular because it is lightweight and compact and is capable of taking pictures having excellent background blur effect as compared with an interchangeable lens apparatus including a focal-length-variable zoom lens system. Accordingly, various kinds of single focal length lens systems usable as imaging lens systems in camera systems have conventionally been proposed, such as single focal length lens systems disclosed in Japanese Laid-Open Patent Publications Nos. 06-130291 and 2004-029641.